THE SOUTHWORTH PLANETARIUM 207-780-4249   www.usm.maine.edu/planet
70 Falmouth Street   Portland, Maine 04103 43.6667° N                   70.2667° W  Altitude:  10 feet below sea level Founded January 1970 Julian Date:  2459373.18 

2020-2021: CXLIII



THE DAILY ASTRONOMER
Tuesday, June 8, 2021
June 2021 Night Sky Calendar  Part II

Finally, we continue the June 2020 night sky calendar.  Today we offer part II and tomorrow part III. 


FRIDAY, JUNE 11:  MERCURY AT INFERIOR SOLAR CONJUNCTION
Today, the swift-footed Mercury moves between the Sun and the comparatively lethargic Earth.    (Mercury revolves more quickly than Earth because it is closer to the Sun.)  The configuration that places Mercury between us and our parent star is called inferior solar conjunction.  Mercury won't be visible now as it is too close to the Sun.    However, when the Sun, Earth and Mercury are precisely aligned during inferior conjunction, we can watch Mercury crossing the Sun's disc.   This direct passage, called a transit, is not common. Mercurian transits occur about 13 times per century.  The next Mercurian transit won't occur until November 13, 2032.

SATURDAY, JUNE 12:  VENUS 1.

5 DEGREES SSW OF THE MOON (SILVER EVENT!!)
skychart.ashx.png
Heart-breakingly gorgeous!  A somewhat peculiar but strangely apt description of Venus and Luna gathered together against the civil twilight.    Tonight one will see the waxing crescent moon (4% illuminated) and Venus in the western evening sky.      Moon-Venus appulses tend to be beguilingly beautiful sights and this latest one is no exception.   Venture out before 9:30 p.m. to see them close to the western horizon.

SUNDAY, JUNE 13:  MOON CLOSE TO MARS  (BRONZE EVENT!)
skychart.ashx2.png
Lovely, but without the heartbreak.     See Mars and waxing crescent moon (10% illuminated) in the western evening sky tonight.     While an observer should experience little trouble finding the brilliant planet Venus, locating Mars is trickier because it is presently 174 times dimmer than Venus.      Venture out by 10:30 p.m. to easily find both the planet and moon tonight. 

TUESDAY, JUNE 15:  THE SMILING CONSTELLATION

corona-borealis-fred-espenak-sq.jpg


Yes, if one observes the night sky closely, one can actually see a "smile" in the stars.  This upward stellar arc is more properly known as "Corona Borealis," or the Northern Crown.   One can see it this evening rising in the eastern sky.       It is the "smile" separating the Hercules Keystone and Bootes the Sheepherder.   (We tell school children that Bootes is the high calorie ice cream cone and Corona Borealis is the smile of the child who is preparing to devour it.)

hercules-corona-borealis-bootes.png


Mythologically, Corona Borealis is the crown given to Ariadne by Dionysius, god of wine and merriment.   Dionysius spied Ariadne as she wept miserably on the island of Naxos.   The poor girl had been abandoned by the caddish Theseus, who had promised to marry her in exchange for helping him escape the Labyrinth in which he and thirteen other Athenian youth were to be imprisoned, along with the flesh craving Minotaur.     Ariadne told him the secret:  tie a skien of thread to the entrance and draw it out while walking through the maze so that it could be followed back toward the opening.    After slaying the Minotaur, Theseus, Ariadne and the other Athenians sailed away from Crete en route to Athens.  On the first night, they stopped at Naxos.   Ariadne awoke the next morning in time to see the ship sail vanishing over the horizon.     Although she was distraught by this abandonment, Ariadne was soon consoled by and eventually fell in love with Dionysius.  Unlike most gods who tended to use mortals as pretty play things, Dionysius was genuinely devoted to Ariadne.  He gave her this crown as a token of his eternal love: a crown he set in stars when his beloved perished.    Among the stars this crown still remains.

Corona Borealis is also known as a "lynchpin" or "bridge" constellation, meaning that it connects seasonal skies.   Corona Borealis is the lynchpin constellation bridging the spring and summer night skies.  Delphinus the Dolphin is the lynchpin constellation connecting the summer and autumn sky.  Perseus connects the autumn to winter sky and Aquarius is the lynchpin between the winter and spring sky.          

THURSDAY, JUNE 17:  FIRST QUARTER MOON



To subscribe or unsubscribe from the Daily Astronomer:
https://lists.maine.edu/cgi-bin/wa?SUBED1=DAILY-ASTRONOMER&A=